Abstract: Objective To observe the expression of collagen IV (COL IV) in cultured rat glomerular mesangial cells (GMCs), and to investigate the role of AMP-activated protein kinase (AMPK) in the process. Methods GMCs were incubated in four groups for 24 hours: control group (glucose 5.6 mmol/L), high glucose group (glucose 22.0mmol/L), low 5-amino-4-imidazolecarboxamide-riboside (AICAR, activator of AMPK) group (0.5mmol/L AICAR＋22.0mmol/L glucose), high AICAR group (1.0mmol/L AICAR＋22.0mmol/L glucose). AMPKα1 mRNA level was measured by RT-PCR, and the protein levels of AMPKα, p-AMPKα and COL4α5 subunit by Western blot analysis. Results Compared with control group, high glucose increased COL4α5 synthesis of GMCs, but reduced AMPKα1 mRNA level and protein levels of AMPKα, p-AMPKα; AICAR suppressed the over-expression of COL4α5, and raised the protein levels of AMPKα, p-AMPKα. Conclusion High glucose can increase COL4α5 synthesis of GMCs, this change maybe correlates with lower expression and activity of AMPK.

Key words: AMPK, high glucose, glomerular mesangial cells, extracellular matrix, collagen IV